Jopen (Dutch pronunciation: [ˈjoːpə(n)]) is a beer brand from Haarlem, the Netherlands.

Jopen beer is a result of the work of Stichting Haarlems Biergenootschap, which was founded in 1992. The mission of the Biergenootschap is to re-create traditional Haarlem beers and bring them to the commercial market. Two recipes were found in the Haarlem city archives that were used as a foundation for 2 initial beers. The first one was a recipe from 1407 and the recreation of this was named Koyt.

In December 1996 the commercial company Jopen BV acquired the beer. The name Jopen refers to the 112 liter beer barrels that were used in early times to transport the Haarlem beer.

Until the end of 1996 Jopen beer was brewed in the Halve Maan brewery in Hulst, after that it was made in the La Trappe brewery in Berkel-Enschot. Since 2001 the Jopen beer brands were brewed in Ertvelde, Belgium, in brewery Van Steenberge. The current brewer is Chris Wisse.

At the end of 2005 it was announced that the old Jacobuskerk in Haarlem would be transformed into a brewery. Since November 11th 2010, the "Jopenkerk' (Jopenchurch) has opened its doors, in the Raaks area, in the city centre of Haarlem. This former church is not only the home of the Jopen brewery but also hosts a cafe and a restaurant.

Jopen won two silver medals at the 2008 World Beer Championship.